Cold-proof composite geotextile and preparation method thereof

Abstract

The application belongs to the technical field of geotextile production, and particularly relates to a cold-proof composite geotextile and a preparation method thereof, which comprises the following raw materials in parts by weight: polyethylene 50-60 parts, ethylene-vinyl acetate copolymer 20-30 parts, modified composite fiber 30-50 parts, modified flaky calcium carbonate 4-10 parts, and submicron inorganic whisker fiber 3-5 parts; the modified composite fiber is prepared from modified pre-oxidized fiber, basalt fiber and nano aerogel. By adding functional modified composite fiber in the polyethylene-vinyl acetate copolymer fiber, the reinforcing and anti-aging effects of the added submicron inorganic whisker fiber and the wear-resistant and pressure-resistant performance of the modified flaky calcium carbonate are combined, so that the overall mechanical strength and service life of the geotextile are significantly improved, the product has excellent flame retardance, temperature resistance, structural stability and durability in a low-temperature environment, and can meet the long-term performance requirements of engineering in different extreme environments.

Description

Technical Field

[0001] This invention belongs to the field of geotextile production technology, specifically relating to a cold-proof composite geotextile and its preparation method. Background Technology

[0002] Geotextiles are permeable fabrics made of synthetic or natural fibers through needle punching or weaving. They are widely used in civil engineering for isolation, filtration, drainage, reinforcement, and protection. By physically separating soil or building materials of different particle sizes, they are used to stabilize soil, control erosion, and improve the performance of civil engineering structures.

[0003] Traditional geotextiles are mostly made of high molecular polymers, including polypropylene, polyester, and polyethylene. Polypropylene is often used for drainage and isolation applications due to its low cost and strong resistance to acid and alkali corrosion, but its UV resistance is weak and it is prone to aging after long-term exposure. Polyester has high tensile strength and is resistant to high temperature and UV radiation, making it suitable for reinforcing roadbeds or protecting steep slopes. However, it is expensive and its strength is easily lost due to long-term contact with alkaline substances such as lime, cement, concrete, and alkaline soil. Its hydrolysis resistance is also poor, and its environmental adaptability is poor. Although polyethylene has excellent chemical resistance, its flexibility is insufficient, limiting its application range. Chinese Patent Publication No. CN106381610A discloses a method for preparing a high-strength, weather-resistant geotextile. The method involves pretreating polyacrylonitrile-based carbon fibers and mixing them with antioxidants, barium stearate light stabilizers, etc., followed by extrusion, filtration, spinning, and consolidation processes to obtain a geotextile blank. Multi-walled carbon nanotubes are then added to dimethylformamide, stirred, and mixed, followed by ultrasonic dispersion with sodium dodecylbenzene sulfonate. The mixture is then uniformly sprayed onto the surface of the geotextile blank and dried to obtain the geotextile. This patented geotextile exhibits high strength, strong resistance to deformation, and good weather resistance, and has broad application prospects.

[0004] However, in recent years, the engineering field has increasingly demanded higher comprehensive performance from geotextiles. Most existing geotextile products have limited functionality, poor cold resistance and flame retardancy, and are particularly prone to brittleness below -20℃ and softening above 60℃ in extreme environments, leading to a sharp drop in performance and making them unsuitable for special climates such as high altitudes, cold regions, and tropical areas. Furthermore, they suffer from low tensile strength, making them unable to withstand the lateral pressure of vehicles on the soil, prone to tearing and creep, resulting in reinforcement failure and causing road surface cracking and slope landslides. Therefore, to meet the increasing construction requirements and address the problems of insufficient strength, poor cold resistance and flame retardancy, and insufficient service life of general geotextiles, there is an urgent need to develop a high-strength, cold-resistant geotextile with certain flame-retardant properties. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies and to provide a cold-resistant composite geotextile and its preparation method. By adding functional modified composite fibers to polyethylene-vinyl acetate copolymer fibers, combined with the reinforcing and anti-aging effects of added submicron inorganic crystalline fiber whiskers, and the wear-resistant and compressive-resistant properties of modified flaky calcium carbonate, the overall mechanical strength and service life of the geotextile are significantly improved. This results in a product with excellent flame retardancy, temperature resistance, and structural stability and durability in low-temperature environments, meeting the long-term performance requirements of engineering projects under various extreme environments.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A cold-resistant composite geotextile comprises the following raw materials in parts by weight: 50-60 parts of polyethylene, 20-30 parts of ethylene-vinyl acetate copolymer, 30-50 parts of modified composite fiber, 4-10 parts of modified flaky calcium carbonate, and 3-5 parts of submicron inorganic crystalline fiber whiskers, wherein the modified composite fiber is prepared from modified pre-oxidized filament fiber, basalt fiber, and nano-aerogel.

[0007] Preferably, the modified composite fiber is prepared by the following method: (1) Add graphene oxide and water to a container, and ultrasonically disperse for 3-5 min to prepare a suspension; dissolve the coupling agent in ethanol to prepare a solution with a coupling agent mass content of 20%; add the pre-oxidized fiber to the suspension and the coupling agent solution, mix, heat to 40-60℃, stir for 20-40 min, filter, and vacuum dry to obtain the modified pre-oxidized fiber; (2) The modified pre-oxidized fiber and basalt fiber are mixed evenly, impregnated with potassium permanganate solution, washed and calcined to obtain composite fiber; (3) Add the composite fiber obtained in step (2) to an ethanol aqueous solution to obtain a suspension, add nano aerogel particles to the suspension, stir until evenly dispersed to obtain a mixed suspension; then heat, solidify, cool and shape to obtain modified composite fiber.

[0008] This application embeds nanoscale aerogel particles uniformly and firmly into a composite membrane fiber web prepared from modified pre-oxidized filament fibers and basalt fibers. The aerogel is not easily detached or escaped, allowing the fibers to interlock more tightly during weaving, forming a more uniform interwoven structure. This tight and uniform interweaving helps to disperse the stress generated in the fabric under stress, avoiding localized stress concentration that could lead to fiber deformation or breakage. As a result, when the fabric is subjected to external forces such as stretching and bending, it can distribute the force more evenly, maintaining good flexibility and softness in low-temperature environments, and improving the fabric's temperature resistance and durability.

[0009] Preferably, the weight ratio of the modified pre-oxidized filament fiber, basalt fiber, and nano-aerogel is 4:5:1.

[0010] Preferably, the nano-aerogel includes any one of mullite aerogel and silica aerogel. The nanofiber aerogel has excellent fire resistance, good high and low temperature resistance, and thermal insulation properties. By mixing it with modified pre-oxidized fiber and basalt fiber, the temperature resistance, flame retardant properties, and durability of the fiber are further improved.

[0011] Preferably, the modified flaky calcium carbonate is prepared by the following method: (1) Heat the calcium carbonate powder to 160-200°C in a calcining furnace and keep it at a constant temperature for 6-10 min. Add it to an ethyl acetate solution and stir at a speed of 900-1100 r / min for 25-40 min. After standing and separating into layers, remove the upper clear liquid to obtain calcium carbonate slurry. (2) Add calcium carbonate slurry to a high-pressure homogenizer and process it under a pressure of 10-25 MPa to obtain flake calcium carbonate slurry. Dry it at a temperature of 110-140℃ for 1.2-1.6 h to obtain flake calcium carbonate. (3) Prepare a suspension by ultrasonically dispersing flake calcium carbonate and graphene oxide with water for 4-6 min, mix the suspension with a coupling agent solution, heat to 45-65℃, stir for 25-45 min, filter and vacuum dry to obtain modified flake calcium carbonate.

[0012] This invention involves heating calcium carbonate powder with a sheet-like structure, causing the spacing between the calcium carbonate layers to expand and increase. Then, the high-speed shearing, high-frequency oscillation, and pressure generated by the instantaneous vaporization of water molecules under high pressure in a high-pressure homogenizer force the calcium carbonate layers to peel apart, forming calcium carbonate with a sheet-like structure. Adding this modified sheet-like calcium carbonate to the raw materials for composite geotextile preparation significantly improves the tensile strength, tensile modulus, flexural strength, and flexural modulus of the composite material, resulting in geotextiles with high strength, high wear resistance, and extended service life.

[0013] Preferably, the submicron inorganic whisker fiber is made of inorganic whisker fiber and sodium lignosulfonate in a mass ratio of 100:1-2.

[0014] Preferably, the inorganic whisker fiber includes one or more of calcium sulfate whisker fiber, silicon carbide whisker fiber, and magnesium oxide whisker fiber.

[0015] This invention selects submicron inorganic whiskers as a toughening agent to improve the toughness of composite geotextiles. Calcium sulfate whisker fibers are fibrous single crystals of anhydrous calcium sulfate, which are dimensionally stable and possess properties such as high temperature resistance, chemical corrosion resistance, good toughness, high strength, wear resistance, and good gas insulation. Silicon carbide whisker fibers are currently the whisker products with the highest hardness, largest modulus, highest tensile strength, and highest heat resistance temperature among synthesized whisker products. Magnesium oxide whisker fibers are extremely fine fibrous single crystals with good heat resistance, insulation, thermal conductivity, alkali resistance, stability, and reinforcing properties.

[0016] Another object of the present invention is to provide a method for preparing a cold-resistant composite geotextile, comprising the following steps: (1) After the inorganic whisker fiber and sodium lignosulfonate are mixed evenly, they are dispersed by an airflow disperser to obtain a submicron inorganic whisker fiber dispersion. Modified flaky calcium carbonate is added to the dispersion and stirred evenly to obtain a mixed filler. (2) Polyethylene, ethylene-vinyl acetate polymer and mixed filler are blended and granulated according to the weight parts, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber; (3) The modified composite fiber and polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. The submicron inorganic whisker fibers added to the cold-proof composite geotextile of this invention provide reinforcement through their high aspect ratio needle-like structure, while surface modification imparts excellent interfacial compatibility, UV resistance and flame retardancy; the flake calcium carbonate can improve the abrasion resistance and compressive strength of the geotextile, significantly improving the mechanical properties and service life of the geotextile, with longitudinal and transverse tear strength ≥110N, which can effectively resist the effects of construction machinery rolling, soil lateral pressure, external tensile force and other effects; 2. The cold-proof composite geotextile of this invention adds composite fibers and submicron inorganic whisker fibers, which gives the geotextile excellent flame retardancy and temperature resistance. The flame retardancy performance meets industry standards, which can effectively delay the spread of flames and quickly self-extinguish after the flame is removed. This can effectively reduce fire hazards and spread risks, avoid safety accidents caused by the flammable properties of materials, and ensure the safety of engineering and the environment. 3. The composite fiber added in this invention is made of modified pre-oxidized fiber, basalt fiber and nano aerogel. Through specific formulation and specific process, the composite fiber has excellent flame retardant properties and high and low temperature resistance. It still maintains good flexibility and softness in a low temperature environment of -60℃, which improves the temperature resistance and long-term performance of geotextile. 4. The cold-proof fabric preparation process of this invention causes the fibers to entangle with each other to form a dense and thick structure, which improves the density and structural stability. No visible cracks or breaks are observed after bending for 48 hours in a low temperature environment of -60℃. 5. The cold-proof geotextile of this invention is suitable for extreme scenarios such as roadbed and bridge maintenance, slope protection, and emergency flood control in high-altitude and cold regions. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. In the absence of conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0019] A cold-resistant composite geotextile comprises the following raw materials in parts by weight: 50-60 parts of polyethylene, 20-30 parts of ethylene-vinyl acetate copolymer, 30-50 parts of modified composite fiber, 4-10 parts of modified flaky calcium carbonate, and 3-5 parts of submicron inorganic crystalline fiber whiskers, wherein the modified composite fiber is prepared from modified pre-oxidized filament fiber, basalt fiber, and nano-aerogel.

[0020] It should be noted that the modified composite fiber was prepared by the following method: (1) Add graphene oxide and water to a container and ultrasonically disperse for 3-5 min to prepare a suspension; dissolve triethoxyvinylsilane coupling agent in 95% ethanol aqueous solution to prepare a silane coupling agent solution with a coupling agent mass content of 20%; add pre-oxidized fiber to the suspension and silane coupling agent solution and mix, heat to 40-60℃, stir for 20-40 min, filter and vacuum dry to obtain modified pre-oxidized fiber; (2) The modified pre-oxidized fiber and basalt fiber were mixed evenly at a mass ratio of 4:5, and a potassium permanganate solution with a mass percentage concentration of 9% was added. The mixture was impregnated at 65°C for 6 minutes, and then washed and calcined to obtain composite fiber. (3) Add the composite fiber obtained in step (2) to an ethanol aqueous solution to obtain a suspension, add mullite aerogel particles to the suspension, the mass ratio of composite fiber to nano aerogel particles is 9:1; stir until uniformly dispersed to obtain a mixed suspension; then heat, solidify, cool and shape to obtain modified composite fiber 1#.

[0021] It should be noted that the modified composite fiber was prepared by the following method: (1) Add graphene oxide and water to a container and ultrasonically disperse for 3-5 min to prepare a suspension; dissolve 3-aminopropyl-triethoxysilane coupling agent in ethanol to prepare a solution with a coupling agent mass content of 20%; add pre-oxidized fiber to the suspension and silane coupling agent solution and mix, heat to 40-60℃, stir for 20-40 min, filter and vacuum dry to obtain modified pre-oxidized fiber; (2) The modified pre-oxidized fiber and basalt fiber were mixed evenly at a mass ratio of 4:5, and a potassium permanganate solution with a mass percentage concentration of 11% was added. The mixture was impregnated at 75°C for 4 min, and then washed and calcined to obtain composite fiber. (3) Add the composite fiber obtained in step (2) to an ethanol aqueous solution to obtain a suspension. Add silica aerogel particles to the suspension. The mass ratio of composite fiber to nano aerogel particles is 9:1. Stir until evenly dispersed to obtain a mixed suspension. Then heat, solidify, cool and shape to obtain modified composite fiber 2#.

[0022] It should be noted that the modified composite fiber was prepared by the following method: (1) Add graphene oxide and water to a container and ultrasonically disperse for 3-5 min to prepare a suspension; dissolve 3-aminopropyl-triethoxysilane coupling agent in ethanol to prepare a solution with a coupling agent mass content of 20%; add pre-oxidized fiber to the suspension and silane coupling agent solution and mix, heat to 40-60℃, stir for 20-40 min, filter and vacuum dry to obtain modified pre-oxidized fiber; (2) The modified pre-oxidized fiber and basalt fiber were mixed evenly at a mass ratio of 4:5, and a potassium permanganate solution with a mass percentage concentration of 10% was added. The mixture was then impregnated at 85°C for 3 minutes, washed and calcined to obtain composite fiber. (3) Add the composite fiber obtained in step (2) to an ethanol aqueous solution to obtain a suspension. Add mullite aerogel particles to the suspension. The mass ratio of composite fiber to nano aerogel particles is 9:1. Stir until evenly dispersed to obtain a mixed suspension. Then heat, cure, cool and shape to obtain modified composite fiber 3#.

[0023] It should be noted that the modified flaky calcium carbonate is prepared by the following method: (1) Heat the calcium carbonate powder to 160°C in a calcining furnace and keep it at a constant temperature for 10 min. Add it to the ethyl acetate solution and stir at a speed of 900 r / min for 40 min. After standing and separating into layers, remove the upper clear liquid to obtain calcium carbonate slurry. (2) Add calcium carbonate slurry to a high-pressure homogenizer and process it under a pressure of 10 MPa to obtain flake calcium carbonate slurry. Dry it at 110°C for 1.6 h to obtain flake calcium carbonate. (3) Prepare a suspension by ultrasonically dispersing flake calcium carbonate and graphene oxide with water for 4 min, mix the suspension with a coupling agent solution, heat to 45°C, stir for 45 min, filter and vacuum dry to obtain modified flake calcium carbonate 1#.

[0024] It should be noted that the modified flaky calcium carbonate is prepared by the following method: (1) Heat the calcium carbonate powder to 180°C in a calcining furnace and keep it at a constant temperature for 8 min. Add it to the ethyl acetate solution and stir at a speed of 1000 r / min for 35 min. After standing and separating into layers, remove the upper clear liquid to obtain calcium carbonate slurry. (2) Add calcium carbonate slurry to a high-pressure homogenizer and process it under a pressure of 15 MPa to obtain flake calcium carbonate slurry. Dry it at 130°C for 1.4 h to obtain flake calcium carbonate. (3) Prepare a suspension by ultrasonically dispersing flake calcium carbonate and graphene oxide with water for 5 min, mix the suspension with a coupling agent solution, heat to 55°C, stir for 35 min, filter and vacuum dry to obtain modified flake calcium carbonate 2#.

[0025] It should be noted that the modified flaky calcium carbonate is prepared by the following method: (1) Heat the calcium carbonate powder to 200°C in a calcining furnace and keep it at a constant temperature for 6 min. Add it to the ethyl acetate solution and stir at a speed of 1100 r / min for 25 min. After standing and separating into layers, remove the upper clear liquid to obtain calcium carbonate slurry. (2) Add calcium carbonate slurry to a high-pressure homogenizer and process it under a pressure of 25 MPa to obtain flake calcium carbonate slurry. Dry it at 140°C for 1.2 h to obtain flake calcium carbonate. (3) Prepare a suspension by ultrasonically dispersing flake calcium carbonate and graphene oxide with water for 6 min, mix the suspension with a coupling agent solution, heat to 65°C, stir for 25 min, filter and vacuum dry to obtain modified flake calcium carbonate 3#. Example 1

[0026] A method for preparing a cold-resistant composite geotextile includes the following steps: (1) Calcium sulfate whisker fiber and sodium lignosulfonate are mixed evenly at a mass ratio of 100:1 and then dispersed by an airflow disperser at a speed of 250 r / min to obtain submicron inorganic whisker dispersion. 4 parts by weight of modified flaky calcium carbonate 1# are weighed and 3 parts by weight of dispersion are added and stirred evenly to obtain mixed filler. (2) 50 parts by weight of polyethylene, 20 parts by weight of ethylene-vinyl acetate polymer and 7 parts by weight of mixed filler are blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber; (3) 30 parts by weight of modified composite fiber 1# and 70 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Example 2

[0027] A method for preparing a cold-resistant composite geotextile includes the following steps: (1) Silicon carbide whisker fiber and sodium lignosulfonate are mixed evenly at a mass ratio of 100:2 and then dispersed by an airflow disperser at a speed of 250 r / min to obtain submicron inorganic whisker dispersion. 5 parts by weight of modified flaky calcium carbonate 2# are weighed and added to 4 parts of the dispersion and stirred evenly to obtain mixed filler. (2) 55 parts by weight of polyethylene, 25 parts by weight of ethylene-vinyl acetate polymer and 9 parts by weight of mixed filler were blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber. (3) 40 parts by weight of modified composite fiber 2# and 80 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Example 3

[0028] A method for preparing a cold-resistant composite geotextile includes the following steps: (1) Magnesium oxide whisker fiber and sodium lignosulfonate were mixed evenly at a mass ratio of 100:1 and then dispersed by an airflow disperser at a speed of 250 r / min to obtain submicron inorganic whisker dispersion. 7 parts by weight of modified flaky calcium carbonate 3# were weighed and 5 parts by weight of dispersion were added and stirred evenly to obtain mixed filler. (2) 60 parts by weight of polyethylene, 30 parts by weight of ethylene-vinyl acetate polymer and 12 parts by weight of mixed filler are blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber; (3) 50 parts by weight of modified composite fiber 3# and 90 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Example 4

[0029] A method for preparing a cold-resistant geotextile includes the following steps: (1) Weigh calcium sulfate whisker fiber and silicon carbide whisker fiber at a mass ratio of 1:1, mix them with sodium lignosulfonate at a mass ratio of 100:2, and then disperse them in an airflow disperser at a speed of 250 r / min to obtain submicron inorganic whisker dispersion. Weigh 10 parts by weight of modified flake calcium carbonate 2# and add 5 parts by weight of dispersion to stir evenly to obtain mixed filler. (2) 60 parts by weight of polyethylene, 25 parts by weight of ethylene-vinyl acetate polymer and 15 parts by weight of mixed filler are blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber. (3) 45 parts by weight of modified composite fiber 2# and 85 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Example 5

[0030] A method for preparing a cold-resistant geotextile includes the following steps: (1) Weigh calcium sulfate whisker fiber and magnesium oxide whisker fiber at a mass ratio of 1:1, mix them with sodium lignosulfonate at a mass ratio of 100:2, and then disperse them in an airflow disperser at a speed of 250 r / min to obtain submicron inorganic whisker dispersion. Weigh 8 parts by weight of modified flake calcium carbonate 2# and add 4 parts by weight of dispersion to stir evenly to obtain mixed filler. (2) 60 parts by weight of polyethylene, 25 parts by weight of ethylene-vinyl acetate polymer and 12 parts by weight of mixed filler were blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber. (3) 45 parts by weight of modified composite fiber 2# and 85 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Example 6

[0031] A method for preparing a cold-resistant geotextile includes the following steps: (1) Weigh silicon carbide whisker fiber and magnesium oxide whisker fiber at a mass ratio of 1:1, mix them with sodium lignosulfonate at a mass ratio of 100:2, and then disperse them in an airflow disperser at a speed of 250 r / min to obtain submicron inorganic whisker dispersion. Weigh 10 parts by weight of modified flaky calcium carbonate 2# and add 5 parts by weight of dispersion to stir evenly to obtain mixed filler. (2) 60 parts by weight of polyethylene, 30 parts by weight of ethylene-vinyl acetate polymer and 15 parts by weight of mixed filler are blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber. (3) 45 parts by weight of modified composite fiber 2# and 90 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Comparative Example 1

[0032] A method for preparing geotextile includes the following steps: (1) Weigh silicon carbide whisker fibers and magnesium oxide whisker fibers at a mass ratio of 1:1, mix them with sodium lignosulfonate at a mass ratio of 100:2, and then disperse them in an airflow disperser at a speed of 250 r / min to obtain submicron inorganic whisker dispersion. (2) 60 parts by weight of polyethylene, 30 parts by weight of ethylene-vinyl acetate polymer and 15 parts by weight of submicron inorganic whisker dispersion are blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber. (3) 45 parts by weight of modified composite fiber 2# and 90 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Comparative Example 2

[0033] A method for preparing geotextile includes the following steps: (1) 60 parts by weight of polyethylene, 30 parts by weight of ethylene-vinyl acetate polymer and 15 parts of modified flaky calcium carbonate No. 2 were blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber. (2) 45 parts by weight of modified composite fiber 2# and 90 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Comparative Example 3

[0034] A method for preparing geotextile includes the following steps: (1) Weigh silicon carbide whisker fiber and magnesium oxide whisker fiber at a mass ratio of 1:1, mix them with sodium lignosulfonate at a mass ratio of 100:2, and then disperse them in an airflow disperser at a speed of 250 r / min to obtain submicron inorganic whisker dispersion. Weigh 10 parts by weight of modified flaky calcium carbonate 2# and add 5 parts by weight of dispersion to stir evenly to obtain mixed filler. (2) 60 parts by weight of polyethylene, 30 parts by weight of ethylene-vinyl acetate polymer and 15 parts by weight of mixed filler are blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber. (3) The polyethylene-vinyl acetate copolymer fiber is placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Comparative Example 4

[0035] A method for preparing geotextile includes the following steps: (1) Weigh silicon carbide whisker fiber and magnesium oxide whisker fiber at a mass ratio of 1:1, mix them with sodium lignosulfonate at a mass ratio of 100:2, and then disperse them in an airflow disperser at a speed of 250 r / min to obtain submicron inorganic whisker dispersion. Weigh 10 parts by weight of modified flaky calcium carbonate 2# and add 5 parts by weight of dispersion to stir evenly to obtain mixed filler. (2) 60 parts by weight of polyethylene, 30 parts by weight of ethylene-vinyl acetate polymer and 15 parts by weight of mixed filler are blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber. (3) 45 parts by weight of basalt fiber and 90 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Comparative Example 5

[0036] A method for preparing geotextile includes the following steps: (1) 60 parts by weight of polyethylene and 30 parts by weight of ethylene-vinyl acetate polymer were blended and granulated, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber; (2) 45 parts by weight of basalt fiber and 90 parts by weight of polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile. Test case

[0037] The performance of the cold-proof composite geotextiles prepared in Examples 1-6 and Comparative Examples 1-5 were tested respectively. The specific test methods are as follows: Flame retardant performance: According to GB / 5454-1997 "Burning performance test of textiles - oxygen index method", the limiting oxygen index (LOI) test was conducted on an oxygen index tester. The sample size was 80mm × 300mm. The higher the LOI value, the better the flame retardant performance. Aging resistance: The sample was treated with 2% hydrochloric acid for 24 hours and then with 2% sodium hydroxide alkaline mist for 24 hours to test the acid and alkali resistance of the product. At the same time, the tensile strength of the product was tested by treating it with UV intensity of 400uW / cm, ozone concentration of 20ppm and temperature of 35℃ for 24 hours. Cold protection performance: The cold protection performance is tested according to the low temperature impact test in FZ / T01007-2025 Determination of Low Temperature Resistance of Coated Fabrics. The lower the test temperature, the stronger the cold protection performance.

[0038] The specific test results are shown in Table 1.

[0039] Table 1 Performance test results for different test cases

[0040] As shown in Table 1, the composite geotextile product prepared in Example 6 exhibits excellent tensile strength, significant acid and alkali resistance, and anti-aging stability, with the strongest low-temperature resistance. The experimental test data from Comparative Examples 1-5 show that adding only one component to the formulation of this invention can significantly impact the overall performance of the product. For example, if only modified composite fibers are added without modified flake calcium carbonate or submicron inorganic crystalline fiber whiskers, the aging resistance of the prepared geotextile is significantly reduced, as shown in the experimental results of Comparative Example 5, and the flame retardant performance also decreases accordingly. Conversely, if modified flake calcium carbonate is not added to the formulation, the modified flake calcium carbonate... The addition of flaky calcium carbonate can enhance the strength of geotextiles. Experimental data from Comparative Examples 3 and 4 show that geotextiles prepared without composite fibers or with conventional basalt fibers exhibit varying degrees of performance degradation, with significantly reduced temperature resistance and aging resistance. This indicates that the composite fibers prepared using the specific method of this invention have a significant impact on the performance of geotextile products. In summary, the experimental data show that the modified composite fibers and modified flaky calcium carbonate obtained using the special formula and specific method of this invention produce the most significant performance improvement. Other methods are not as effective as those of this invention.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A cold-resistant composite geotextile, characterized in that, The raw materials include the following parts by weight: 50-60 parts of polyethylene, 20-30 parts of ethylene-vinyl acetate copolymer, 30-50 parts of modified composite fiber, 4-10 parts of modified flaky calcium carbonate, and 3-5 parts of submicron inorganic whisker fiber. The modified composite fiber is prepared from modified pre-oxidized filament fiber, basalt fiber, and nano-aerogel.

2. The cold-proof composite geotextile according to claim 1, characterized in that, The modified composite fiber was prepared by the following method: (1) Add graphene oxide and water to a container, and ultrasonically disperse for 3-5 min to prepare a suspension; dissolve the coupling agent in ethanol to prepare a solution with a coupling agent mass content of 20%; add the pre-oxidized fiber to the suspension and the coupling agent solution, mix, heat to 40-60℃, stir for 20-40 min, filter, and vacuum dry to obtain the modified pre-oxidized fiber; (2) The modified pre-oxidized fiber and basalt fiber are mixed evenly, impregnated with potassium permanganate solution, washed and calcined to obtain composite fiber; (3) Add the composite fiber obtained in step (2) to an ethanol aqueous solution to obtain a suspension, add nano aerogel particles to the suspension, stir until evenly dispersed to obtain a mixed suspension; then heat, solidify, cool and shape to obtain modified composite fiber.

3. The cold-proof composite geotextile according to claim 2, characterized in that, The weight ratio of the modified pre-oxidized filament fiber, basalt fiber, and nano-aerogel is 4:5:

1.

4. The cold-proof composite geotextile according to claim 2, characterized in that, The nano-aerogel includes any one of mullite aerogel and silica aerogel.

5. The cold-proof composite geotextile according to claim 1, characterized in that, The method for preparing the modified flaky calcium carbonate includes the following steps: (1) Heat the calcium carbonate powder to 160-200°C in a calcining furnace and keep it at a constant temperature for 6-10 min. Add it to an ethyl acetate solution and stir at a speed of 900-1100 r / min for 25-40 min. After standing and separating into layers, remove the upper clear liquid to obtain calcium carbonate slurry. (2) Add calcium carbonate slurry to a high-pressure homogenizer and process it under a pressure of 10-25 MPa to obtain flake calcium carbonate slurry. Dry it at a temperature of 110-140℃ for 1.2-1.6 h to obtain flake calcium carbonate. (3) Prepare a suspension by ultrasonically dispersing flake calcium carbonate and graphene oxide with water for 4-6 min, mix the suspension with a coupling agent solution, heat to 45-65℃, stir for 25-45 min, filter and vacuum dry to obtain modified flake calcium carbonate.

6. The cold-resistant composite geotextile according to claim 1, characterized in that, The submicron inorganic whisker fiber is made of inorganic whisker fiber and sodium lignosulfonate in a mass ratio of 100:1-2.

7. The cold-proof composite geotextile according to claim 6, characterized in that, The inorganic whiskers include one or more of calcium sulfate whisker fibers, silicon carbide whisker fibers, and magnesium oxide whisker fibers.

8. A method for preparing a cold-resistant composite geotextile according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Inorganic whisker fibers and sodium lignosulfonate are mixed evenly according to the mass ratio and then dispersed by an airflow disperser to obtain submicron inorganic whisker fiber dispersion. Modified flaky calcium carbonate is added to the dispersion according to the weight ratio and stirred evenly to obtain mixed filler. (2) Polyethylene, ethylene-vinyl acetate polymer and mixed filler are blended and granulated according to the weight parts, and melt-spun to obtain polyethylene-vinyl acetate copolymer fiber; (3) The modified composite fiber and polyethylene-vinyl acetate copolymer fiber are placed in a mixer and mixed evenly to obtain a mixture; the mixture is fed into a twin-screw extruder and melted, extruded, spun and drawn, laid, needle punched and hot rolled to obtain the cold-proof composite geotextile.

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